Impulse vibrators



June 26, 1962 E. P. PEREGRlNE ETAL 3,040,591

IMPULSE VIBRATORS Filed Nov. 5, 1959 3 Sheets-Sheet l June 1962 E. P.PEREGRINE ETAL 3,040,591

IMPULSE VIBRATORS 5 Sheets-Sheet 2 Filed Nov. 5, 1959 ll o0 June 1962 E.P. PEREGRINE ETAL 3,040,591

IMPULSE VIBRATORS Filed Nov 5, 1959 3 Sheets-Sheet 3 United rates Thisinvention relates to impulse vibrators and is concerned primarily withthe use of such vibrators in pile driving equipment, the object beingthe reduction in weight and complication of field equipment generallyused for this purpose.

According to one aspect of the invention there is provided a mechanicallinkage for use in an impulse vibrator, comprising, in combination, afloating link, a rocker link, a rotary crank journalled to one end ofthe floating link, a lower end of the rocker link being journalled tothe floating link intermediate the length of said floating link, a freeend of the floating link having a mass, a prime mover being arranged tomove said mass through the rotation of said crank so as to generateoscillatory impulses the force which is greater in one radial directionin the plane transverse to the crank than in other directions.

' According to another aspect of the invention an impulse vibratorconstructed in this manner is provided with a plurality of linkages sothat all forces along the operative axis arising from the motions of thelinkages are summated and all other forces and couples arising therebyare balanced out.

The invention will now be described with reference to the accompanyingdrawings in which:

FIGURE 1 is a diagrammatic illustration of the mechanical linkage andits associated parts,

FIGURE 2 is a perspective view of an embodiment of the invention, withthe linkages omitted,

FIGURE 3 is a perspective view of the outer frame of the embodiment inFIGURE 2,

FIGURE 4 is a perspective view of the inner frame of the embodiment inFIGURE 2, and

FIGURE 5 is a scrap perspective view of a linkage used in the embodimentin FIGURE 2.

Referring to the drawings, FIGURE 1 shows an outer frme 2' attached tothe head of a pile 4', the arrow indicating the operative direction ofthe pile. An inner frame 6' is supported on leaf springs 8 the ends ofwhich are fixed in the outer frame 2, the inner frame 6' being thusmovable against the springs along the operative axis of the pile 4. Thestiffness of the springs is such that the inner frame 6 is unable torock transversely to this axis and if required guides (not shown) may.be fitted between the outer frame 2' and innerframe 6' to ensure thatthey are not displaced transversely relative to each other. 'Inaddition, stops may be fitted to limit the relative axial motion.

A prime mover 10' rigidly attached to the inner frame 6' is connected todrive flywheel 12 which is suitably mounted on bearings 14' to the innerframe. A crank pin 16 on the flywheel 12' has journalled to it one endof a floating link 18'.

Beam 20' rigidly attached to the outer frame 2' carries a shaft 22' onwhich the upper end of rocker link 24' is journalled, its other endbeing pivotally connected to an intermediate point on the length offloating link 18'. The mass of link 18 is concentrated in its free end.

Rotation of the flywheel 12 in the direction of arrow A causes thecentre of mass of the free end of the floating link 18' to follow a pathindicated by the broken line B. Over the portion CDE of the path B themotion atent G is relatively slow but it accelerates quickly to a higherspeed over the portion EC, this latter portion occupying some 90 ofcrank movement. 0n reaching point E, the mass is constrained to changeits path suddenly and its inertia is thereby destroyed, appearing as atension in rocker link 24' and thereby transmitted as a driving impulseon the pile 4'. The inner frame 6' is also impelled to follow thisimpulse but only to the extent that the flexure of the springs 8 inflictan accelerative force on the flywheel bearings 14. The springs thustaking the-reaction of the inner frame 6' with its associated flywheel12 and motor 10, the mass accelerated by the driving impulse is kept ata minimum and the acceleration produced is correspondingly increased.

It will be seen that the mechanism described is an application of thefour bar linkage with an eccentric weight located on an extension of thefloating or free link so that when the crank link attached to the otherend of the floating link is rotated more or less uniformly, as thevarious inertias permit, the rocker link is made to exert a transientforce of high order on what is commonly regarded as the fixed link ofthe system.

There will be other forces produced in the motion of the linkage thatwill act along the operative axis, e.g. that from the eccentricity ofthe flywheel crank, but these are of a lowerorder than the main impulseand serve only to maintain the pile in a state of motion in the periodsbetween main impulses.

Other stray forces will occur transversely to the operative direction.To counter these further linkages may be added as explained hereinafterso synchronised with the first linkage that forces equal and opposite tothose generated by the first linkage are produced in the case of straytransverse forces whereas in the case of forces acting along theoperative axis, their resultant is additive.

FIGURES 2, 3, 4 and 5 illustrate an embodiment of the invention in apile driver. In this arrangement the stray transverse forces and couplesare balanced out by using three flywheel-linkage systems. The flywheelaxes are parallel and co-planar, the two outer, auxiliary systems beingco-axial and located equidistantly from the central main system. Each ofthe outer systems has half the inertia of the central system. The outerflywheels rotate in the opposite sense to the main flywheel and thesystems are so synchronised that their operative impulses occursimultaneously.

The machine comprises an outer frame 2 to the underside of the base ofwhich the pile-driving tool is rigidly attached, and which supportsthrough leaf springs 8 an inner frame 6 carrying flywheels 12a, 12b, 12cdriving motor 10 and the connecting drive therebetween. As statedhereinbefore, vertical guides and stops may be fitted between the innerand outer frames.

The outer frame 2 is made up of a base 28 which serves as an oil sumpand has attachment means for the tool. Secured above the base are theends of leaf springs 8 carrying inner frame 6 and vertical pillars 26.Rigidly connected to the tops of pillars 26 is a beam 20 carrying abearing shaft or shafts 30 for three rocker links (of which one is shownat 2,4) of the linkages.

. The inner frame 6 comprises three pairs of rigid webs 32a, 32b, 32ccarrying pairs of stub shafts 14a, 14b, 14c on which the flywheels 12a,12b, 12c are respectively journalled, the flywheels 12a, being mountedon pairs of stub shafts 14a, 14c on centre-line 13 and the flywheel 1212being mounted on the pair of stub shafts 14b on centre line 15. The webs32a, 32b, 320 are connected at their lower ends to a rigid structure 32mounted on the centre of the leaf springs 8. Extending upwardly andrigidly connected to the Webs is a structure 34 housing the inductionmotor 10. Not shown in FIGURE 4 is a rigid structure 34 extendingupwardly from the webs 32a, 32b, 326. This structure may be integralwith the webs or it may be rigidly bolted or welded thereto. On both endfaces of housing 34 two layshafts 38 are suitably mounted and arerotated in opposite senses by a chain drive 36. A further chain-belt(not shown) from a second sprocket wheel situated inside housing 34 oneach layshaft 38 takes the drive to sprocket wheels (not shown) integralwith or rigidly attached to the flywheels 12a, 12b, 120 of themechanisms, two of the shafts driving the main flywheel 12b and one eachthe auxiliary flywheels 12a, 12c. Alternatively, the drive to theflywheels may be taken by gearwheels instead of chains and sprockets.

Provision is made for adjustment of the chain drive to allowsynchronisation of the three rotating systems. This is achieved byincorporating a friction clutch in the outer sprocket-wheels of each ofthe four laysh-afts 38.

The links 18, 24 of each mechanism are symmetrically disposed about acentral plane to obviate flexural stresses upon them. FIGURE 5,illustrating a linkage shows the arrangement which is common to allthree sets of linkages. The flywheel 12 is divided into two websconnected by crank pin 16, the space between the pair of webs being wideenough to allow the rocker link 24 to move freely between their innerfaces.

Two lubricating pumps 46 mounted one on each end of the outer frame 2are actuated by an eccentric 42 on each of the two outer flywheels 12a,12c, the eccentrics contacting spring-loaded roller followers 44attached to the pump pistons. Each pump delivers lubricating oil fromthe sump in base 28 to a common manifold (not shown) supplying oil toall the bearings. A non-return valve is fitted in each delivery linefrom pump to manifold.

When assembled for operation the complete apparatus is provided withcovers to maintain the interior dust-free and s improve the life of thebearing surfaces of the moving parts.

Balancing of the stray forces may be achieved by other arrangements thanthe one described. Two systems of equal inertia may be arranged withtheir corresponding parts in the same planes, or, two systems each halfthe inertia of a third system may be arranged equidistantly above andbelow the third system.

The invention reduces the amount and therefore the cost of work to bedone in pile driving and increases the rate at which piles may bedriven. Further, orthodox pile driving plant may be dispensed with and alighter prime mover such as an electric motor or internal combustionengine substituted for the usual steam plant employed.

The scope of the invention is not limited to pile driving. The mechanismis equally applicable to other ap plications requiring oscillatingimpulse forces. It can be used, for example, to assist the motion of aplough through the ground, or in the operation of such apparatus as amechanical hammer. 'It may also be used for the extraction of piles.

What we claim and desire to secure by Letters Patent 1s:

1. Impulse vibrator comprising a plurality of mechanical linkages and arotary prime mover wherein each linkage includes operatively connectedwithin an interconnected inner frame and outer frame, a floating link, arocker link and a flywheel with a crank member thereon, a first journalat one end of said floating link, a free end of predetermined massextending from a second journal at an intermediate point along thelength of said floating link, said first journal being operativelyconnected to said crank member, said second journal being operativelyconnected to the lower end of said rocker link, said flywheel beingrot-atably connected to said inner frame and the upper end of saidrocker link being operatively connected to said outer frame throughwhich the oscillatory impulse is applied, said linkages being soarranged that all forces along the operative axis arising from themotions of the linkages are summated and all other forces and couplesarising thereby are balanced out.

2. Impulse vibrator comprising a plurality of mechanical linkagesaccording to claim 1, wherein said inner frame is secured to said outerframe in such manner that it is resiliently movable thereto along theoperative axis of the vibrator.

3. Impulse vibrator comprising a plurality of mechanical linkagesaccording to claim 1, wherein in each linkage the crank member and itsflywheel, the floating link and the rocker link are symmetricallydisposed about a central plane.

4. Impulse vibrator comprising three mechanical linkages according toclaim 1, wherein two of the linkages are arranged equidistantly on eachside of the third linkage, each having half the inertia of the thirdlinkage and rotating in the opposite sense to the third linkage, allthree linkages having co-planar and parallel axes and being capable ofsynchronisation so that their operative impulses occur simultaneously.

5. Pile driver employing a plurality of mechanical linkages and a rotaryprime mover wherein each linkage includes operatively connected withinan inter-connected innor frame and outer frame, a floating link, arocker link and a flywheel with a crank member thereon, a first journalat one end of said floating link, a free end of predetermined massextending from a second journal at an intermediate point along thelength of said floating link, said first journal being operativelyconnected to said crank member, said second journal being operativelyconnected to the lower end of said rocker link, said flywheel beingrotatably connected to said inner frame and the upper end of said rockerlink being operatively connected to said outer frame through which theoscillatory impulse is applied and said inner frame is secured to saidouter fi'ame in such manner that it is resiliently movable thereto alongthe operative axis of the vibrator, said linkages being so arranged thatall forces along the operative axis arising from the motions of thelinkages are summated and all other forces and couples arising therebyare balanced out.

6. A mechanical linkage for an impulse vibrator comprising, incombination, a supporting frame, a floating link, a rocker link and arotary crank, said crank being r tatably connected to said frame andjournalled to one end of the floating link, a lower end of the rockerlink being jou-rnalled to the floating link intermediate the length ofsaid floating link and an upper end of the rocker link being journalledto said frame, a free end of the floating link having a mass, a primemover secured to said frame being arranged to move said mass through therotation of said crank so as to generate an oscillatory impulse theforce of which is greater in an operative direction than in an opposite,return direction.

7. Mechanical linkage operatively connected in an impulse vibratorcomprising in combination, a support frame, a flywheel journalled tosaid frame with a crank thereon, a rocker link having an upper endjournalled to said frame and a floating link, said crank beingjournalled to one end of the floating link, a. lower end of the rockerlink being journalied to the floating link intermediate the length ofsaid floating link, a free end of the floating link having a mass, aprime mover secured to said frame and being arranged to rotate saidflywheel to move said mass so as to generate an oscillatory impulse, theforce of which is greater in one direction in the plane transverse tothe crank axis than in other directions.

8. Mechanical linkage according to claim 7 wherein the flywheel and saidlinls are operatively connected within an interconnected inner frame andouter frame, said flywheel being rotatively connected to said innerframe and the upper end of said rocker link being operatively connectedto said outer frame through which said oscillatory impulse is applied.

3,040,591 5 a 6 9. Mechanical linkage according to claim 7, wherein theflywheel and its crank, the floating link and the rocker the flywheeland said links are operatively connected withlink are symmetricallydisposed about a central plane. in an interconnected inner frame andouter frame, said flywheel being rotatively connected to said innerframe References Cited in the file of this Pawnt and the upper end ofsaid rocker link being operatively 5 NIT connected to said outer framethrough which said oscil- U ED STATES PATENTS latory impulse is applied,said inner frame being secured 465,363 Diehl Dec. 15, 1891 to said outerframe in such a manner that it is resiliently 1,762,939 Wittel June 10,1930 movable thereto along the axis of said oscillatory impulse. 2,20,724 Robins May 14, 1940 10. Mechanical linkage according to claim 7wherein 10 2,346,070 Fuller Apr. 4, 1944

